1. International Civil Aviation Organization Colloquium on Environmental Aspects of Aviation Aircraft Emissions - The Way Forward Willard Dodds, Chairman ICCAIA Noise and Emissions Committee Montreal, 9-11 April 2001

2. Elements of ICAO CAEP Approach
Terms of Reference
Technical Feasibility - Safety
Environmental Benefit
Economic Reasonableness
Environmental Balance/Tradeoffs
Noise
Climate Change
Local Air Quality
Program Balance
Source Reductions (Technology)
Operational Measures (Airlines and ATC)
Market Based Measures
Unique ICAO Resources Address Complex Issues

3. Emission Issues Issue Key Species Mitigation
Climate Change - Carbon Dioxide (CO2) - Fuel Efficiency - Water Vapor - Operational Measures - NOx - Combustor Design
Local Air Quality - NOx Combustor Design - Carbon Monoxide (CO) - Operational Unburned Hydrocarbon (HC) Measures Smoke/Soot

4. Local Air Quality Continuous emissions reductions
ICAO Data Bank provides current emissions certification data
Required design/test margins ensure that certificated product emissions are below ICAO limits
Ref: The Boeing Company

5. 70% Fuel Efficiency Improvement over 40 Years
Climate Change
Continuous fuel efficiency improvements driven by market forces
Market based measures are being considered by ICAO
Long term - open emissions trading
Near term - voluntary programs
70% Fuel Efficiency Improvement over 40 Years

6. CO2/NOx Trade
Higher engine pressure ratio and bypass ratio reduce CO2/improve fuel efficiency (SFC) and facilitate noise reduction
SFC
SFC (lb/lb-hr, or EI NOx) 10 20 30 40 50 60
Overall Pressure Ratio

7. CO2/NOx Trade
Higher engine pressure ratio and bypass ratio reduce CO2/improve fuel efficiency (SFC) and facilitate noise reduction
Higher pressure ratio requires higher flame temperature, increasing NOx formation rate NO
SFC X
SFC (lb/lb-hr, or EI NOx) 10 20 30 40 50 60
Overall Pressure Ratio

8. CO2/NOx Trade
Higher engine pressure ratio and bypass ratio reduce CO2/improve fuel efficiency (SFC) and facilitate noise reduction
Higher pressure ratio requires higher flame temperature, increasing NOx formation rate
Better NOx technology needed to avoid increased emissions NO
SFC X
SFC (lb/lb-hr, or EI NOx) 10 20 30 40 50 60
Overall Pressure Ratio

9. Emissions Technology Outlook
Continuous technology improvement has substantially reduced all emissions from modern engines
Government and industry emissions reduction technology programs are underway
Barriers to wider introduction of these technologies:
high development and certification investment with low production volume
durability, operability, reliability & production cost risks
environmental tradeoffs
unclear policy objectives
unrealistic short term technology expectations
ICAO WG 3 Long Term Goals Group is addressing technology transition issues

10. Emissions Technology Expectations
17 ICCAIA - Working Group 3 Papers prepared for CAEP/5
Papers support IPCC Special Report projection of 20% improvement in fuel efficiency between 1997 and 2015
NOx reduction technology is progressing faster than the IPCC scenario for NOx emissions 30-50% below CAEP/2 limits by 2020
Concerns relative to the rate of future progress due to
uncertain research funding
environmental and technological tradeoffs/priorities
increasing challenge to improve on current technology 1

11. Summary and Conclusions
ICAO is uniquely qualified to set aviation environmental standards
Brings together resources to balance complex trade-offs
Avoids proliferation of confusing, inconsistent and counterproductive local rules
Globally harmonized approach for a global industry
Manufacturers continually work to improve emissions technologies
Need consistent and consolidated scientific basis for valid trade-off analyses
Aircraft emissions reduction efforts should be part of a balanced program including improved operational factors
Successful long term research requires continuous support and consistent goals
CAEP/6 Work Program has proper elements to move forward on local air quality and climate